Semen Quality Lower in Men when Mother’s Beef Consumption High During Pregnancy

Shanna H. Swan, Ph.D.
University of Rochester
R01ES009916

Men whose mothers consumed beef more than 7 times per week during pregnancy had lower sperm counts as adults according to new research results from NIEHS-grantee Shanna H. Swann at the University of Rochester. The research team conducted an epidemiologic study of 387 men. Semen quality went down as mothers’ beef consumption went up, but Swann, the lead author, cautions that the results just raise the issue. More research is necessary before any substantial conclusions can be reached.

The study points out that all the men were able to father a child without medical assistance. However, the 51 men whose mothers ate the most beef had sperm counts classified as sub-fertile according to the World Health Organization. In contrast, the men whose mothers ate the least beef had average sperm concentrations 24 percent higher. The men’s consumption of beef was not associated with decreased semen quality nor was the mothers’ consumption of other meats.

The studies authors suspect that in utero exposure to growth hormones and other chemicals present in beef may alter testicular development. This is but one explanation for these findings; there are several other possibilities including pesticides in cattle feed and other lifestyle factors during pregnancy.

Citation: Swan SH, Liu F, Overstreet JW, Brazil C, Skakkebaek NE. Semen quality of fertile US males in relation to their mothers’ beef consumption during pregnancy. Hum Reprod. 2007 Jun;22(6):1497-502.